Linux divides its physical RAM (random access memory) into chucks of memory called pages. Swapping is the process whereby a page of memory is copied to the preconfigured space on the hard disk, called swap space, to free up that page of memory. The combined sizes of the physical memory(RAM) and the ...

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19
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4answers
22k views

How do I tell if my Windows server is swapping?

I'm using Process Explorer to monitor my windows server while it reconstructs some data. It's primarily a CPU intensive process, but I want to make sure it's not swapping. How can I tell if it is ...
2
votes
1answer
694 views

Server refuses to use swap partition

We are running a server with 23 cores (cpuinfo shows 22 as the highest process number) and 66 Gig RAM. The development team here is running some apps, which hogs memory. I have observered that: 1. ...
37
votes
4answers
16k views

Why don't EC2 ubuntu images have swap?

I started a couple servers on EC2 and they don't have swap. Am I doing something wrong or is it that the machines just don't have any?
9
votes
10answers
6k views

How big should the swap partition be?

for some years, I've read that it's a good idea to create a swap partition having the double space of my RAM. does it still apply today? or this isn't needed anymore? I have a server with 8 GiB of ...
41
votes
12answers
29k views

How much SWAP space on a high memory system?

How should I decide what size to make my swap size on a new linux machine (Debian) with a reasonably large amount of Ram (2-4 GB)? Do I really need swap space defined?
4
votes
4answers
3k views

How can I monitor what process is swapping?

I have a linux webserver. It's running Apache and a python based web application and postgres. It's quite slow. By running ab (apache benchmark) and vmstat I could see that it was swapping while ...
6
votes
6answers
19k views

What is swap memory?

I am using RAM for storing some of my database tables and the others are stored in hard disk. Today I came to know that my processes are using swap memory. Now what is swap memory and how can I ...
24
votes
5answers
18k views

swap partition vs file for performance?

What is better for performance? A partition closer to the inside of the disk will have slower access times, and we must wait for the drive to switch between the OS and swap partitions. On the other ...
8
votes
1answer
611 views

Create swap file on a running Linux machine

Our company web sites have just been moved from a shared host to a VDS, as the hosting company plans on retiring the less than completely reliable shared hosting server(s). The VDS only has 256MB of ...
8
votes
2answers
3k views

Ubuntu Linux: Process swap memory and memory usage

My Ubuntu eats more memory than the task manager is showing: sudo ps -e --format rss | awk 'BEGIN{c=0} {c+=$1} END{print c/1024}' 2750.29 free -m total used free ...
6
votes
3answers
20k views

How do I tell what process is causing kswapd to be in use?

I see kswapd using 100% CPU... how can I tell on which process's behalf kswapd is being used so much?
1
vote
4answers
522 views

Should Swap be used like this?

I have a server with Dual Nehalem Quad Core Xeon 5520 and 12GB DDR3 RAM. The server's average memory usage is only around 10-15%, yet the Swap used shows 10%+. Is this normal, or could something be ...
10
votes
6answers
9k views

SSD for swap on Ubuntu server

Currently I am reading SSD reviews and I wonder how much exactly I will benefit if I move the 24 GB swap from 7200rpm HDD to SSD. Does anyone implemented swap space on SSD? Is this generally good ...
4
votes
3answers
1k views

Do I need SWAP on my server?

I have a particular server : 50GB SSD for the OS (CentOS) , 128GB of RAM and 320GB SSD for MySQL. I'm wondering if I really need SWAP? I often read that 2GB is good even with lots of RAM. This ...
10
votes
11answers
10k views

Linux server is only using 60% of memory, then swapping

I've got a Linux server that's running our bacula backup system. The machine is grinding like mad because it's going heavy in to swap. The problem is, it's only using 60% of its physical memory! ...
10
votes
8answers
9k views

Should I completely turn off swap for linux webserver?

Recently my friend told me that it is a good idea to turn off swap on linux webservers with enough memory. My server has 12 GB and currently uses 4GB (not counting cache and buffers) under peak load. ...
4
votes
2answers
4k views

Where should my swap partition/s live when using software RAID1? Performance? LVM?

When I search around for example RAID1 installations, it seems that admins tend to place their swap partition under RAID1. To me, it is more intuitive to have two disks, each with a large partition ...
35
votes
9answers
10k views

Linux: how to explicitly unswap everything possible?

I've launched something that took lots of memory and now everything lags a lot. I guess all applications' memory has gone to swap in order to free some space for the memory-intensive process, and now ...
7
votes
2answers
3k views

How can I create a swap partition on Amazon EC2 with ephemeral storage?

This is the output of df -k: Filesystem 1K-blocks Used Available Use% Mounted on /dev/xvda1 10317860 7059008 2734732 73% / none 847584 0 ...
4
votes
1answer
2k views

Why does host swap out VMs when there are 16GB of buffer cache and swappiness = 0? [duplicate]

I have a desktop running Ubuntu Quantal using OpenStack Folsom on an Intel i5 with 32 GB RAM and 2 GB swap. I'm running 7 VMs each sized like a EC2 m1.small, so 1.7 GB RAM each. I'm using KVM. As I ...
4
votes
4answers
3k views

Who is using the swap memory and why?

My database server is using 191MB of swap space - but also shows 182MB of free RAM The box is a dedicated MySQL server, running Debian Lenny. How can I determine who and why is filling the swap ...
5
votes
4answers
6k views

Constantly Increasing swap size in Linux and Swap space not being reclaimed?

I have a 8GB RAM linux box on which 4 tomcat servers are running. One of the them is set to 3000MB memory(jvm -Xms and -Xmx setting) and others are set to 1500MB. The swap partition is also set to ...
5
votes
7answers
5k views

Do I even need a swap partition with Linux?

I have a core 2 laptop with 4gb of ram. I use the machine for browsing, network stuff and simple programming. (I use this machine to host a small ftp and web server semi-occasionally.) Would there be ...
3
votes
4answers
1k views

Running swap on RAID10 or RAID5?

In follow-up to this previous question (and it's excellent answer), I am curious to know if running swap on a RAID5 might not be better than on a RAID10. My thinking is that you might lose a bit on ...
8
votes
6answers
9k views

CentOS How Much SWAP for 16GB of RAM?

How much SWAP would you give a CentOS install on a dual Quad Core XEON with 16GB of RAM that is going to be running a php website with a mysql backend - medium/heavy load?
5
votes
4answers
2k views

When is swap moved back to physical memory?

When is swap moved back to physical memory in Linux? Is it only on demand, ie. when it's needed? Or is swap slowly transfered to physical memory when the computer is not on high load?
4
votes
4answers
831 views

System swapping … how do I figure out what the problem is

I have an ubuntu vps running that has about 300MB of memory, of which only 20% or less is free right now ... My question is, how can I figure out what particular program I'm running that is causing it ...
2
votes
3answers
4k views

(CentOS) Adding swap file failed

Im trying adding swap file by following this guide: http://www.redhat.com/docs/manuals/linux/RHL-8.0-Manual/custom-guide/s1-swap-adding.html Everything is fine, but starting swapon /swapfile, I got ...
1
vote
2answers
1k views

memory leak? RHEL 5.5. RSS show ok, almost no free memory left, swap used heavily

i encounter a very instresting problem, and it seems that some physical may disapper quietly. i am very puzzled, so if anyone could give some help, I would be very appreciated. here is my top show: ...
0
votes
1answer
873 views

How do i enable memory overcommit on solaris?

on a solaris 8 server with a specific workload, how do i turn on memory overcommit (à la Linux) ? # Memory size: 65536 Megabytes sun[root] # vmstat 1 procs memory page disk ...
2
votes
2answers
141 views

Swap memory exhausting server even site has small visitors

I have CentOs 6.5 running on a 32bit VPS host. It is running only php-fpm, nginx, and mysql. I have a site that gets on average 20 visitors per day, but I am recently getting this message from my ...
1
vote
1answer
378 views

e2fsck on a low-memory machine: can I get more out of scratch_files or swap?

I am running CentOS 6 on a 32-bit machine with 1 GB of RAM. I have a 1TB external HDD that I am trying to run e2fsck on. It runs for about an hour and a half and then fails with Error storing ...
1
vote
1answer
2k views

Centos server not using SWAP properly and getting OOM

Recently I've been having some serious memory issues with my server. Just the other day, my server became completely unresponsive, and oom-killer started killing services at random (httpd, php, etc). ...
0
votes
1answer
232 views

Why the system information message when accessing an Ubuntu server doesn't match free -m?

Each time I SSH into my AWS Ubuntu servers I see a system information message, showing load, memory usage and packages available to install, like this: Welcome to Ubuntu 12.04.3 LTS (GNU/Linux ...